Incorporation Of Broadband Access Technology In A Telecommunications Engineering Technology Program

The so-called “last mile” of the telecommunications network, which links residences and business locations to the network, has traditionally been the last bastion of old technology. Residential voice service is still mostly provided via an analog signal over a pair of copper wires that connects the telephone to a switching system in a central office. The high-speed digital technology employed by modern switching systems and inter-office transmission systems does not extend to most residences. The local access network is a landscape of copper wires bound into large cables, splices, cross-boxes and other equipment that has provided voice-grade service over the years. However, the landscape is changing dramatically as both residential and business customers demand more and more bandwidth for a growing number of services including highspeed Internet access and video as well as voice. Telcos such as AT&T and Verizon as well as Multi-Service Operators (MSOs) are both vying to provide the “triple play” (voice, data and video) to these customers. In order to provide the triple play, service providers are introducing digital transmission and optical fiber, which have revolutionized long-haul communication, to the local access network. The Telecommunication Engineering Technology program at RIT is responding to this trend by providing courses and laboratory facilities to introduce students to the associated technology. Our Telecommunication Systems Laboratory now features both passive optical network (PON) and hybrid fiber/coax (HFC) technology. These are two leading approaches to provide broadband access to support the triple play. In addition, we are developing new courses to cover topics such as video transmission and broadband network engineering. This paper presents the current status of our laboratory and course development along with our plans for future enhancements. Introduction This paper consists of two parts: a review of communication requirements and technology in the local access network and a report on how this area is being addressed by the Telecommunication Engineering Technology Program and Rochester Institute of Technology. The Local Access Network The local access network is sometimes referred to as the “last mile” of the information highway. It has also been known as the local loop network or the “outside plant”. It is the part of the telecommunications network that connects individual subscribers (residential and business) to a network node (e.g., a telco central office). The local access network was originally designed to provide analog voice service. It was required to transmit a limited range of audio signals (up to about 4000 Hz), DC control signals (on/off hook and dial pulses) and ringing voltage (about 90 VAC @ 20 Hz) over a distance that normally ranged up to about 13 miles (1). The traditional medium of choice has been twisted pairs of copper wire, supplemented with load coils for distances (i.e., loop lengths) exceeding 18000 feet. Even as long-distance networks migrated to microwave radio, then to coaxial cable and finally to optical fiber, the twisted pair continued to rule the local access network. In the 1970s, broadcast television service providers began installing coaxial cable systems to distribute television from centralized “head ends” to individual subscribers. These systems, which consist of coaxial cable and broadband RF amplifiers, could carry both VHF and UHF television signals and for many subscribers offered superior quality compared to over-the-air broadcast. Thus many communities were served by two separate local access networks providing two different services and run by two different types of business. However, changes in both technology and the regulatory environment soon began to blur the distinctions, especially with regard to services offered. Both the telcos and the cable TV service providers began to offer Internet access with steadily increasing bandwidth. The multi-service operators (or MSOs, as the cable TV service providers are now called) had the advantage of having a broadband network in place and could use this bandwidth for downstream video, two-way data and even two-way voice. The concept of “triple-play” service (voice, data and video from a single service provider) was born. At the same time, the MSOs were converting their coax networks to hybrid fiber/coax (HFC) networks that use optical fiber to deliver service to points near the subscribers and coax for the final distribution network. The addition of optical fiber improved signal quality while significantly reducing the number of broadband amplifiers in the network. In order to compete, telcos had to upgrade their access networks. Digital Subscriber Line (DSL) technology can squeeze more bandwidth out of twisted pairs, but not enough for a triple play. While some telcos are patching together a triple play by bundling satellite service, others, such as Verizon and AT&T, are investing heavily to upgrade their local access networks. Verizon is making perhaps the most radical change by converting to all-fiber local access networks (fiber to the home or FTTH) using passive optical network (PON) technology. As of October 2007, Verizon’s FTTH service, which they call FiOS, was available to 8.5 million households and FiOS TV service was available to 4.7 million households (2). Thus today we have both telcos and MSOs building broadband access networks and offering triple-play services. And both of these industries require engineers who understand broadband technology, service and standards. The RIT Telecommunication Engineering Technology Program The College of Applied Science and Technology at RIT has introduced a BS program in Telecommunications Engineering Technology in the early 1990s and added an MS program in 2002 (3). The BSTET program is derived from an electrical engineering technology program and the programs are nearly identical for the first two years. Upper level undergraduate students and graduate students take specialized courses in telecommunications, including voice and data transmission, switching and signaling technology, network planning and management and telecommunication policy and regulation. Until recently the program has had little emphasis on broadband transmission in general and video transmission in particular. Whether students study electronics, transmission lines, antennas or even fiber optics, they normally learn to address the amplification, transmission or propagation of single sinusoidal signals or single modulated sinusoidal carriers. In June 2006 the Society of Cable Telecommunications Engineers (SCTE) announced the formation of the SCTE Cable College at RIT (4) to “deliver a comprehensive cable-centric educational program for telecom technicians and engineers in the cable industry”. This partnership between RIT and the SCTE, together with the general developments in broadband technology outlined above, has led to an increasing emphasis on video and broadband technology in the Telecommunications Engineering Technology program. In the sections that follow, we present descriptions of the first two new courses to address this technology and the laboratory facilities that have been acquired and installed to support classroom learning with hands-on experience. Courses Courses have been selected based on a number of inputs, including • Specific requests from representatives of SCTE, as reflected in their proposed curriculum • Meetings with the Industrial Advisory Board for the Telecommunications Engineering Technology program • The background and expertise of the Telecommunications Engineering Technology faculty • The overall goals of the Telecommunications Engineering Technology program With regard to the last point, courses outside the scope of engineering technology (e.g., cable installation) were referred to other departments in RIT. The initial courses are introductory with regard to video and broadband, but build on a basic background of most telecommunications or electrical engineering technology students. They also supplement existing courses that have been deemed important by the SCTE, such as transmission systems, communication systems and fiber optic technology. In addition to traditional students, RIT in general and the TET program in particular address the needs of students who are working in industry and/or are distant from the RIT campus. Most courses are available in the evening or online (online courses may require an on-campus weekend for laboratory practice). Principles of Digital Video This course explores the creation, processing, and distribution of raw and compressed digital video formats over different communication networks such as wireless, cable, and fiber. The course has a special emphasis on digital television applications such DTV, HDTV, and IPTV. The course also explores different video distribution network topologies and protocols for the Internet, cable, and enterprise networks for video conferencing. This course is a foundation course for the knowledge of digital video, digital video processing, and distribution of digital video over a variety of networks. The student will be prepared to take advanced courses in digital video processing after taking this course. The purpose of the course is to enable students to: • Demonstrate a knowledge of the basic terminology in digital processing • Understand basic concepts of video formats • Demonstrate a knowledge of various coding and compression techniques • Demonstrate understanding knowledge of digital video processing and its use in industry • Demonstrate knowledge of issues of synchronous and asynchronous distribution of video over the internet and other networks. • Perform digital processing activities on video streams. • Perform networking processes on digital video • Demonstrate knowledge of the impact of standards on the digital video industry. The course is divided into the following topics: